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%I #8 Jul 25 2022 09:12:48
%S 2,4,8,10,14,16,20,22,26,28,30,32,34,38,40,44,46,50,52,56,58,60,62,64,
%T 68,70,74,76,80,82,86,88,90,92,94,98,100,104,106,110,112,116,118,120,
%U 122,124,128,130,134,136,140,142,146,148,150,152,154,158,160,164,166,170,172,176,178,180,182,184,188,190,194,196,200,202,206,208,210,212
%N Numbers k such that the smallest prime that does not divide them is of the form 4m+3.
%C Numbers k such that A053669(k) is in A002145.
%C The asymptotic density of this sequence is Sum_{p prime, p == 3 (mod 4)} ((p-1)/(Product_{q prime, q <= p} q)) = 0.3662357207... . - _Amiram Eldar_, Jul 25 2022
%t f[n_] := Module[{p = 2}, While[Divisible[n, p], p = NextPrime[p]]; p]; Select[Range[200], Mod[f[#], 4] == 3 &] (* _Amiram Eldar_, Jul 25 2022 *)
%o (PARI)
%o A053669(n) = forprime(p=2, , if(n%p, return(p))); \\ From A053669
%o A353529(n) = (3==(A053669(n)%4));
%o isA353531(n) = A353529(n);
%o k=0; n=0; while(k<100, n++; if(isA353531(n), k++; print1(n,", ")));
%Y Cf. A353530 for the complement among the even numbers.
%Y Cf. A002144, A053669, A353526, A353529 (characteristic function).
%Y Differs from A342050 for the first time at n=77, where a(77) = 210, the term that is missing from A342050, as A342050(77) = 212.
%K nonn
%O 1,1
%A _Antti Karttunen_, Apr 25 2022
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